Power driven pencil sharpeners



March 27, 1962 M. J. GREEN 3,026,848

POWER DRIVEN PENCIL sHARPENERs Filed May 11, 1959 l 29 f i@ y 48 26 i2 II( mi "MMHIII NIIHHHHHL "MNHN,

Fatented- Mar, 2?', 19.162

3,026,348 PDWERDRWEN PENGIL SHARPENERS Martin i. Green, 730 Milburn St.,Evanston, lll. naar May 11,1959, ser. No. 812,513 3' Claims. (Cl.1Z0-96) This invention relates in generalvto power driven pencilSharpeners, and more particularly to such devices which are capable ofsharpening the lead in amechanical or automatic pencil.

The useof automatic or mechanicalpencils by draftsmen in all elds ofdrawing has increased to the point of substantially supplanting use ofthe ordinary wooden pencil, but with the mechanical pencils only the oldmanual methods of sharpening have been available, which are notoriouslyslow andldirty.

A principal object of this invention, therefore, is to provide a clean,quick and easy way in which to reduce the end of a lead in a mechanicalpencil to a point, or a substantially conical shape of selected length,so as to cause lines drawn thereby to be of a desired width. This objectis attained by providing a portable electrically driven Sharpener withenclosedcuttermeans for reducing the end of the iead to the desiredshape, and means for receiving thelower end of the body of a mechanicalpencil and the lead extending therefrom to present the latter to thecutter means while preventing contact of the pencil body therewith.

Another object of the invention is to insure a` clean lead aftersharpening and one always having. the desired selected shape, and toprevent breaking thereof during sharpening. This object is assured byproviding a cutter means comprising a rotor having a vertical axis andcarrying cutter elements pivoted onhorizontal axes for move,- mentbetween a normal, at rest position and anoperative position in responsetocentrifugal forces developed by rotation of the rotor.

A further important object is to avoid scattering of lead dust from orby such a Sharpener by enclosing the cutter means in a suitable` housingfor collecting the lead dust, and providing the housing with an aperturethrough which the end of the lead may be introduced for reduction by thecutter means, with such aperture being only large enough to accommodatethe lead.

Another object of the invention is to eliminate the necessity ofmanually operating a motor controlling switch as a separate operation inthe use of such a pencil sharpener by providing means automaticallyoperable to cause energization of the Sharpener motor in response tomovement of a pencil with respect thereto in introducing the exposed endof its lead into position for reduction by the cutter means.

A further object of the invention is to facilitate reduction of theexposed end of the lead in a mechanical pencil, so as to cause linessubsequently drawn thereby to be of a desired selected width, byproviding guide means adjustably mounted on the pencil Sharpener housingto enable presetting of the pencilv to expose the proper length of leadto result in the desired selected shaping of the end thereof whenpresented to the cutter means.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description7 which, whentaken in connection with the accompanying drawings, discloses apreferred embodiment thereof.

In the drawings:

FIGURE l is a side elevation of a pencil Sharpener embodying thefeatures of this invention, with those portions thereof above the motorshown in vertical section, and the operating parts in inoperativeposition;

FiG. 2 is a vertical sectional view similar to the upper portion of FIG.l showing the cutter elements and switch closing means in operative oractive position; and

FIG. 3 is a top plan view of the Sharpener with the cover member removedand part of the switch controlling lever broken away.

Referring more particularly to PEG. l of the drawings, reference numeral11 indicates in general a portable, electrically driven Sharpener forautomatic pencils which comprises a base portion 12 of any suitableconstruction housing an electric motor having a vertically extendingshaft 13 protruding upwardly through a suitable motor housing comprisingpart of the base portion 12 and supplied in well-known manner byelectrical energy from a suitable source, comprising the cord or leads14, through the agency of a microswitch 15 interconnected in seriestherewith by means of leads 16. This motor switch 15 is of well-knownconstruction and includes a member 17 normally spring-urged outwardly(to the left in FiGS. 1 and 2) to maintain the switch'closed and therebyto provide the motor with electrical energy from the line 14. Theswitch15'y is enclosed within a housing 1d that is mounted upon the motorenclosing portion of the base 12 by any desired means, such as a bracket19. it should be noted that the lower part of the base 12 preferably isweighted in any suitable manner, as by means of lead or other heavymetal.

Pivotally mounted at 21 on the switch 15 proper or its housingl is aswitch controlling or opening means comprising an angular lever 22 withwhich a suitable spring Z3 cooperates. As shown, the spring 23 ismounted upon a stud 24 extending outwardly from the lever 22 and isinterposed between the latter and thecasing of the switch 15 above thepivot 21 so as normally to urge the lower end of the lever 22 outwardly,or to the right in FiGS. l and 2, to movethe switch member 17 againstthe'action of its spring to open the switch 15. The motor thus normallyis maintained de-energized as a result of the spring 23 resilientlyretaining thelever 22 in its active, switch opening position of FIG. 1.

Above the stud 24, the lever 22 extends upwardly through a suitableaperture 25Sl in the top of the switch housing 1S, and terminates in aninwardly extending horizontal portion preferably provided with a roller26 pivotally mounted in any suitable manner at its inner end. Theleftmost portion of this roller 26 is disposed substantially in verticalalignment with the axis of the motor shaft 13 so as to be in the path ofmovement of the lower end 27 (FIG. 2) of the body portion of amechanical pencil 2S during the movement of the latter to present itslead 29 to the Sharpener, in a manner to be described hereinafter.During such movement of the pencil 2S, the lower end 27 thereof willcontact the roller 26 to move the switch controlling lever 22 in aclockwise direction about its pivot 21 from its normal position of FIG.l and against the action of spring 23 to its inoperative position ofFIG. 2. The switch member 17 thus will -be released to close the switch15 and cause the motor to be energized.

Rotary cutter means comprising a plurality of cutter elements 31 and amounting block 32 therefor are secured to the upper end portion of themotor shaft 13 in any suitable manner. As herein illustrated, the lowerportion of the mounting block or rotor 32 is provided with a borecentrally thereof which slidably receives the upper end of the motorshaft 13, and the rotor is secured to the shaft by means of a suitablehorizontally disposed set screw 33. In the present embodiment oftheinvention, fourcutter elements 31 are employed. To accommodate thesecutter elements, the upper portion of the mounting block or rotor 32, asbest seen in FIG. 3, is provided with two vertically extending slots 34at right angles tok each other and intersecting coincident with thevertical center 3 line of the rotor and of the motor shaft 13. Each slot34 accommodates two of the cutter elements 31, each of which ispivotally mounted therein intermediate its ends by means of a horizontalpin 35 subtending the slot and rigidly secured to the mounting block 32in any suitable manner.

Each cutter element 31 comprises a first-class lever with respect to itspivotal mounting 35, with its lower arm having a weight 36 securedthereto in any suitable manner and, when in its inoperative position orposition of rest of FIG. l, being maintained thereby in contact with theadjacent peripheral surface of the rotor or mounting block 32. The upperarm of each element 31 above its pivot 35 is angularly disposed withrespect to the lower arm thereof as best illustrated in FIG. 1, and isformed as a cutter blade 37. The angular relationship between theseupper portions of the cutter elements 31 and their lower weighted arms36 and the disposition of the cutter blades 37 relative to theirrespective pivots 3S are such that upward swinging movement of theweights 36 is positively limited by abutting engagement of the lowerinner end portions of the several cutter blades 37 with each other, asillustrated in FIG. 2.

Completely surrounding and enclosing this cutter means is a hollowreceptacle comprising an annular body portion 38 and a cover member 39removably mounted thereon. The body portion 38 preferably is disposedcoaxially with the motor shaft 13 and the cutter means, and is eithersecured in any suitable manner at its lower end to the motor housingbase portion 12 or -forrned integrally therewith. The cover member 39preferably is made considerably thicker than the annular body portion 38to provide sufficient weight to prevent its accidental displacement,while obviating any necessity for any special means for removablyretaining the same on the body portion of this receptacle.

The central portion of the cover member 39 is provided with pencil guideand lead inlet means comprising a stepped bore coaxial with the motorshaft 13 and the cutter means, when the cover is in place, andconsisting of an upper main portion 41 for receiving and guiding thelower end of a mechanical pencil, and a reduced lower portion 42interconnected at its upper end therewith to provide a shoulder 43. Thelower portion 42 of this bore is of such diameter as to slidably receivethe largest size of lead 29 normally employed in a mechanical pencil,and the shoulder 43 functions to limit downward movement of the lowerend of the pencil, as illustrated in FIG. 2.

The neck portion of the removable cover member 39 through which theenlarged part 41 of its bore extends is provided at one side with anaperture 44 extending therethrough and communicating with the bore 41 toaccommodate the inner end of the switch controlling or opening lever 22and its roller 26. This aperture 44 is made only suiciently large topermit free movement of the members 22, 26 between their positions ofFIGS. 1 and 2, and to enable removal of the cover member 39 when theparts are in their positions of FIG. l without disturbing or actuatingthe members 22, 26. This neck portion of the cover member 39 also isprovided, preferably opposite the aperture 44, with a at or horizontallydisposed shelf 45 above which is adjustably mounted a gauge bracket 46.This bracket 46 is a right-angled member having a horizontally extendingarm with a slot 47 therein of a width substantially equal to thediameter of the smaller portion 42 of the cover bore and which is openat its cuter end. The vertical portion of the bracket 46 is slotted forvertically adjustable movement on, and relative to, a suitable set screw48.

When the annular body portion 38 of the cutter enclosing receptacle ispermanently secured to or formed integrally with the base portion 12,mounting of the cutter means on the motor shaft 13 by means of the setscrew 33 might present some difficulties. Consequently, a

suitable access plug 49 may be provided in the lower portion of thecontainer body 38 in horizontal alignment with the screw 33, so thatremoval of this plug will enable the screw 33 readily to be tightened orloosened.

Operation It will be appreciated that the Sharpener unit 11 hereinbeforedescribed is portable but is of sufficient weight to prevent accidentaldisplacement from a supporting surface to eliminate the possibility ofany movement of the unit or malfunctioning as a result of the rapidrotation of the cutter elements 31 and rotor 32 by the motor. It willalso be readily understood that rotation of the motor, through its shaft13 and the rotor 32, rotates the several cutter elements 31 about thevertical axis of the cutter unit and the shaft 13, and that when theunit thus is rotated, centrifugal force will cause the weights 36 tomove outwardly from their at rest or inoperative position of FIG. l toswing the cutter elements about their horizontal pivots 35 to theirterminal position of FIG. 2. As previously explained, such terminalposition of the cutter elements is determined by abutting engagementbetween the lower inner ends of the several cutter blades 37. In thisterminal position of the cutter elements, the blades 37 opposite eachother deline a definite angle, as shown in FIG. 2, which is that whichwill be given to the lower end portion of any piece of lead 29 presentedto the cutter unit.

While any pencil lead 29 presented to the cutter means thus will be cutat its lower end to this particular angle, any pencil lead may besharpened to cause lines drawn thereby to be of a desired width bypresenting only a certain predetermined end length of lead to the cuttermeans. This can be accurately determined because of the shoulder 43 andits cooperation with the lower end 27 of a pencil to definitely limitdownward movement of the pencil relative to the cutting means, and theposition to which the upper horizontal leg of the gauge bracket 46 isadjustably set relative to the shelf 45. With this guide bracket in itsuppermost position, as illustrated in FIGS. l and 2, the operator placesthe lead 29 of the pencil 28 in the slot 47 of the guide means, asillustrated in broken lines in FIG. l, and extends the lower end of thelead 29 until it rests upon the shelf 45. With the lead so adjusted, itwill be sharpened to the finest possible point when the pencil and leadare moved through the guide and supporting means 41, 42 to theirlowerrnost position of FIG. 2. The shorter the length of lead presentedto the cutter means, the broader will be the lines drawn by the pencil,because the wider will be the resulting end surface of the sharpenedlead. Thus, to sharpen any lead to a particular desired degree orcondition less than a sharp point, it is only necessary to reset theguide bracket 46 to some suitable position lower than that shown in theinstant drawings. Since the shoulder 43 of the cover member 39definitely limits the lowerrnost position to which a pencil 28 may bemoved, when the sarne is placed in the unit as illustrated in FIG. 2,the distance between the newly set and lower position of the horizontalportion of the gauge bracket 46 and its uppermost position of thedrawings will be directly proportional to the degree of bluntness towhich the pencil lead will be trimmed.

After the lead has been set to the desired length, insertion downwardlyof the lower end 27 of the pencil 28 into the unit will cause the lowerend 27 of the pencil automatically to displace the motor switchcontrolling lever 22 from its normal position of FIG. 1 to its inactiveposition of FIG. 2, against the action of the spring 23, to permitspring closing of the switch 15 to cause energization of the motor.Conversely, removal of a pencil from its position of FIG. 2 will resultin automatically de-energizing the motor in response to the action ofspring 23 returning the lever 22 to its active position aoaasas of FIG.l in which the lower end of the lever contacts the switch member 17 toopen the switch.

It will be appreciated that the cutting action of the elements 31 is notpositive, since it depends not only upon their rotation about thevertical axis of the motor shaft 13, but also upon the action ofcentrifugal force upon the weights 36. Consequently, a smooth cleancutting action upon the pencil lead presented thereto Will result withthis mechanism. And because of the manner in which such sharpening iseiiected, the sharpened lead will be clean and completely free of anyresidual lead dust. This eliminates any necessity for the operator toclean or wipe the lead off after it has been sharpened. And the leadremoved in sharpening, or any resulting dust, cannot escape from theenclosing receptacle 38, 39, since the only opening therefrom, thereduced bore portion 42, is substantially filled by the lead and isclosed by the lower portion 27 of the pencil.

This pencil Sharpener may readily be cleaned and the accumulated leadand lead dust removed therefrom merely by removing the cover member 39and tipping the unit toward, or turning it over above, a Wastereceptacle, or the like, adapted to receive such cuttings. While thepresent embodiment of the invention has been designed specifically foruse with automatic pencils, it will be appreciated that the same couldbe adapted for use with the ordinary wooden lead pencil by changing theshape of the cover aperture or guide and inlet means 41h-43,

lt is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it Will beapparent that various changes may be made in the form, construction andarrangement of the parts without departing from the spirit and scope ofthe invention or sacricing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A Sharpener for the lead extending from the lower end of the body ofa mechanical pencil, comprising rotatable cutter means, and a receptaclesurrounding said cutter means for collecting lead in dust form resultingfrom operation of said cutter means in sharpening said lead, saidreceptacle having a readily removable cover frictionally mounted thereonwith vertically disposed guide means for receiving the lower end of saidpencil to present said lead to said cutter means and having a portionwith a diameter intermediate those of said lead and said pencil bodyterminating in a substantially horizontal shoulder for limiting downwardmovement of said pencil body to prevent contact between the latter andsaid cutter means, said cutter means comprising a rotor having avertical axis coaxial with said guide means, and a plurality of cutterelements pivotally mounted on said rotor on horizontal axes, each ofsaid cutter elements comprising a weighted lower end and a cutter bladeat its upper end of lesser weight than, and held in an outer inoperativeposition by, said weighted lower end when said rotor is at rest andswingable inwardly into active position in response to rotation of saidrotor.

2. -In a Sharpener according to claim l, means for limiting movement ofsaid cutter blades in their inward swinging when they assume apredetermined angular relationship with respect to each other.

3. In a Sharpener according to claim 2, gauge means mounted on saidreceptacle 'for cooperation with said pencil to determine the properlength of lead extending therefrom to effect the desired shaping by saidcutter means of the end of the lead when the latter is presented to thecutter means and movement of the pencil is limited by said guide means.

References Cited in the le of this patent UNITED STATES PATENTS 836,712Rush Nov. 27, 1906 2,618,240 Haase Nov. 18, 1952 2,657,672 Angell Nov.3, 1953 FOREIGN PATENTS 284,427 Germany May 26, 1915 402,079 GermanySept. 13, 1924 266,661 Switzerland May 1, 1950 753,531 Great BritainJuly 25, 1956 958,815 Germany Feb. 21, 1957

